The present invention is directed toward a production system for animal feed and more particularly, toward a continuous process for turning food waste into dried, nutritionally balanced animal feed.
Food waste obtained from restaurants, institutional facilities, schools, military bases, and fish and poultry processing is commonly used to make dried animal feed because it contains a high level of nutrients. There are many techniques and procedures well known in the art by which dried animal feed is produced from food waste. However, a problem associated with processing food waste into animal feed is that inconsistent product results when typical batch processing is used. That is, batch processing involves smaller amounts of food waste being processed at any given time. This does not allow for the mixing of the food waste into a uniform mixture. As a result, an analysis of the final product formed on one day may differ significantly from a product formed on a different day or even product formed in a different batch on the same day.
Another problem associated with processing food waste into animal feed is that this waste typically has a high moisture and water content. In order to rid the waste of moisture, it is often mixed with a solid material. Various drying techniques and apparatus may also be used in order to reduce the moisture level of the waste.
One type of drying apparatus is a spray dryer. The material to be dried is sprayed into a confined space through which heated air is caused to flow and effect vaporization of moisture form the material. A dry solid results. This technique, however, requires a large amount of heat and mechanical energy.
Another drying technique uses a fluidized bed dryer. A fluidized bed dryer includes a bedplate with holes. The material to be dried is placed on the bedplate. Heated air flows upwardly through the holes at desired volume and velocity levels in order to vaporize the moisture. This technique, however, does not work well with all materials. That is, because these solids have a high moisture content, they tend to agglomerate into large masses. As a result, the heated air has difficulty penetrating these masses, the agglomerated material retains moisture, and only the outside of the mass gets dried.
U.S. Pat. No. 5,596,815 to Rice et al discloses a material drying process which removes moisture from a solid's base material by forming the material into compacted pellets and then passing heated air around the pellets to effect removal of moisture by vaporization of the same. The problem with this technique is that as the moisture level is reduced, the beneficial water content of the pellet may also be reduced. Therefore, valuable nutrients may be lost.